I wouldn't describe my hands as 'ultra dry' all the time, but they do get uncomfortably dry and a little sore in the winter months from being out in cold weather and probably dehydrating from central heating too, leaving them in a bad condition come Spring.
The key ingredient in all of the Lanolips products in Lanolin which comes from wool and it's a super moisturiser because it can hold 200% of its own weight in water! You can find out more of the science bit (if you're a boffin type and need to know these things) from the Lanolips site here.
I've been using this hand cream for the last couple of weeks and it really provides a heavy-duty level of moisture. So much so that I found the best time to apply it is at night - it doesn't leave a stickiness, but you can feel it on your hands if you see what I mean? It's described as leaving a 'silky veil' on the skin. The other reason I applied it at night is because I'm not over-keen on the smell - to me it smells like talcum powder, but I can live with that seeing as it's such a good hand cream, oh and fab for dry feet too.
I also let my Mum try this out as she's always complaining of dry hands and she really loves it - I don't think I'm getting it back!